I thought this was a pretty interesting article to share, even though it is a Part 2 of a two part series.  This article really does a good job in breaking down how encrypted communication works from the aspect of public key infrastructure (PKI).  It actually reminded me of an encryption book I read a while back, Cryptography Decrypted which was also a very nice book in terms of easily breaking down encrypted communications.  Even if you don’t deal with this stuff, it is always good to know if the opportunity ever comes up.  Especially since PKI can be done for free, this info is nice to have.

Key establishment and authentication are the building blocks of network security. Also, these two are also probably the toughest problem in network security. In the following two sections we look at the basic concepts of threshold cryptography which forms the basis of most key establishment and authentication schemes that are being discussed for multihop ad hoc networks.

Threshold Secret Sharing
One of the most prominent solutions to the problem of key establishment and authentication is the use of certificates. Any two nodes in a network may secure (provide confidentiality, data integrity, authentication and nonrepudiation) their communication using certificates. However, issuing and validating certificates requires the deployment of public key infrastructure (PKI).

The use of PKI relies on a trusted third party (the certificate authority (CA)) to verify the identity and authenticity of other nodes. Therefore, the use of PKI and PKC helps create a trust model in the network where all nodes inherently trust the CA. Note that this means that if a node trusts the CA, it will also trust the identity of another node if the CA verifies this identity.

Let’s do a short recap of the role of CA in a PKI. Supposing that Bob wants to talk to Alice using PKC, the following sequence takes place:

1. Bob asks the CA for Alice’s public key.[more]

Tags: Encryption